Pump



June 14, 1938 B. c. WILLIAMSON 2,120,772

PUMP

Filed Aug. 9, 1935 4 Sheets-Sheet l @KMA QEmme 14, 1938.' B. c. WILLIAMSON PUMP Filed Aug. 9, 1935 4 Sheets-Sheet 2 Irv s 4 Wi uvY//Anlzw u Il. lll.. mwmwuw Il ,s f. .lll'llllf `lune 14, 1938.

B. c. WILLIAMSON PUMP Filed Aug. 9, 1955 4 Sheets-Sheet 3 Patented June 14, 1938 UNITED STATES PATENT OFFICE Application August 9,

12 Claims.

This invention relates to pumps and more particularly to a pump which is especially constructed for installation and operation i-n deep wells having `small bores or holes wh-ere a pump occupying a minimum amount of space is necessary.

One of the principal objects of this invention is the production of a simple and efficient pump wherein one of the pistons or buckets is operated hydraulically simultaneously with the operation of a mechanically operated piston or bucket.

Another object of this invention is the production of a simple and eflicient pump wherein the liquid lifting pistons or buckets mounted in the casing are actuated lhydraulically.

A still further object of this invention is the production of an efficient apparatus for elevating liquid by means of a suction pump whereby the liquid is elevated first through pushing action of the piston or bucket upon the liquid to force the liquid above the piston, and then the liquid is lifted b-y the piston upon its upstroke.

Other objects and advantages of the present invention will appear throughout the following specication and claims.

In the drawings:

Figure l is a vertical section through the casing of the pump showing the pistons or buckets on the down stroke;

Figure 2 is an enlarged sectional View of the upper end of the casing and upper piston or bucket;

Figure 3 is a transverse section taken on line 3 3 of Figure 2;

Figure 4 is an enlarged vertical sectional view of the casing showing the hydraulically operated piston on its down stroke;

Figure 5 is a vertical sectional View similar to Figure l through the casing showing the parts on the up or discharge stroke;

Figure 6 is an enlarged vertical section through the casing showing the hydraulically operated piston or bucket on the up or discharge stroke;

Figure 'l is a vertical section through the casing showing the pistons or buckets operated hydraulically, the parts being shown in their down stroke position;

Figure 8 is a vertical section through the casing, certain parts being shown in elevation and the parts being shown in their up stroke or discharge position; l

Figure 9 is a vertical sectional View of a further modied form of the hydraulically operated pump, showing the buckets in the down-stroke position;

1935, Serial N0. 35,541

Figure 10 is a similar view showing the buckets in the up-stroke position; and

Figure l1 is a vertical section through a modified form of the pump showing a pair of booster pumps connected to the by-pass pipes for passing the pressure around the piston rod.

By referring to the drawings, it will be seen that I5 designates the outer casing which is preferably of an elongated tubular structure of suiiicient length to fit within the well I6. 'This tubular casing I5 is preferably closed at its upper end, as indicated at I'I, and is provided with a discharge spout I8 which extends laterally from the upper end of the casing I5. The lower end I9 of the casing is open and is braced by means of suitable radiating ribs which ribs support in the center thereof an upstanding internally threaded socket 2| (note the enlarged detail in Figure 6).

A tubular barrel 22 is mounted within the outer casing I5 and ts snugly Within the casing I5, as shown in Figures 1 and 5. This tubular barrel 22 is adapted to rest at its lower end upon an annular shoulder 23 formed near the bottom of the casing I5 and the barrel 22 carries at its lower end a plurality of converging depending arms 24 which carry an externally threaded stud 25, the stud 25 being adapted to be threaded into the socket 2| for anchoring the lower end of the barrel 22 in a resting position upon the annular flange 23.

An enlarged externally threaded pipe 26 is mounted in the upper end of the casing I5 and carries at its lower end a pair of laterally extending lugs 21 which lugs 2l travel between the spaced track flanges 28 formed upon the inner face and at the upper end of the barrel 22. This arrangement will permit the enlarged pipe 26 to reciprocate within the barrel 22 and will also anchor the pipe 26 against independent rotation within the barrel 22, thereby enabling the barrel 22 to be rotated with the pipe 26 to' cause the threaded stud 25 to be seated within the threaded socket 2I for anchoring the barrel 22 in a set position upon the iiange 23. This arrangement will permit the removal of the barrel 22 for repair or replacement without the necessity of removing the casing I5. Annular bearing rings 29 are threaded upon the enlarged pipe 26 and arranged in spaced relation to constitute a bracing means for holding the pipe 26 in proper alignment and preventing the bending of the operating rods. The upper end of the pipe 26 carries a web 3|] having an internally threaded socket 3I at its center for receiving the externally threaded end of the mechanically operated rod 32, which rod 32 passes through the stufng box 33 carried by the top |1 of the casing l5, and this operating rod 32 may be connected to any suitable or desired operating mechanism. It should be understood that the pipe 26 is of sufrlcient length and the parts may be of sufficient length to accomplish the desired results.

The lower end of the pipe 26 is provided with a web 34 having a centrally located internally threaded socket for receiving the externally threaded hollow pipe 36. A piston or bucket 31 is anchored upon this hollow pipe 36 and is preferably heldin place through the medium of threaded collars 33. The piston or bucket 31 is preferably provided with a plurality of upwardly turned leather cups 39 of the conventional type which are anchored in engagement with the piston through the medium of securing bolts 46.

The piston or bucket 31 is provided with vertically extending ports 4l and flap valves 42 are carried by the top face of the piston or bucket 31 to permit the passage of liquid vertically through the ports 4| and to automatically close and seal the ports against a return downward iiow. It should be understood that this bucket 31 or piston 31 is anchored to reciprocate and move with the threaded pipe` 36 upon which the bucket or piston 31 is mounted.

A tube 43 is arranged to extend vertically in a centrally located position within the barrel 22 and this tube 43 is braced by means of the radiating bracing rods 44 which are secured to the tube 43 at spaced intervals and are also anchored in engagement with the inner face of the barrel 22. A stuffing box 45 is carried by the upper end of the tube 43 and a stuiiing box 46 is carried by the lower end thereof (note Figures 2 and 4). The lower end of the hollow pipe 36 is reciprocably mounted within the upper end of the tube 43 and passes through the stufling box 45. The lower end of the pipe 35 carries a plug 41, and a bleeder pipe 48 extends vertically through the plug 41 and communicates with the interior of the hollow pipe 36 to prevent the tube 43 from becoming air bound under the action of the reciprocating piston rod hereinafter described. The vertically extending bleeder pipe 48 is supported upon a partition 49 carried by the tube 43 in spacedA relation to the limit of the downward stroke of the pipe 36, within the tube 43, as is shown in Figure 4.

A vertically extending plunger rod 56 is carried within the barrel 22 and the upper end of this plunger rod 56 is reciprocably mounted within the lower end of the tube 43, the lower end of the piston rod 50 being mounted within a lower tubular casing 5| which tubular casing carries a stuffing box 52 at its upper end to constitute a seal around the piston rod 5B, as shown in Figure 4. The tube 43 is provided with a check valve 53 and a pop-off valve 54 for the purpose of safety, and the tubular casing 5| is provided with a check valve 55 and a pop-off safety valve 56 located near the limit of the up stroke of the piston rod 56 in the tube 43 and the tubular casing 5|. A pair of by-pass pipes 51 form a communication between the interior of the tubing 43 just above the partition 49 in order to form a communication with the lower closed end 41 ofthe pipe 36 and the lower end of the tubular casing 5| below the bottom or lower end of the piston rod 50,'as shown in Figure 4. A piston 60 is anchored upon the piston rod 50 intermediate the tube 43 and the tubular Vcasing 5| and carries a plurality of upturned leather cups 6|. A plurality of ports 62 are formed in the piston 60 and these ports are closed against downward flow by the flap valves 63, which iiap valves are readily opened to permit upward flow through the piston on its down stroke.

The operation of the device is as follows:-

Upon the downstroke of the operating rod 32 the pipe 26 will be forced downwardly carrying the piston 31 downwardly and this will open the valves 42 and permit the passage of liquid up through the ports 4|. As the piston 31 is moved downwardly the pipe 36 which is closed by the plug 41 at its lower end, will slide downwardly through the tube 43 and force the liquid which is contained within the tube 43 down through the by-pass pipes 51 and into the lower end of the tubular casing 5|. This liquid will act against the bottom end of the piston rod 56 thereby forcing the piston upwardly to lift the liquid above the piston60 in an upward direction, the ilap valves 63 at this time remaining closed. Upon the reverse stroke or up stroke, the piston 31 will move upwardly closing the valves 42 to prevent down ow through the ports 4| and the piston 66 will then move downwardly opening the flap valves 63 and permitting the iiow of liquid through the ports 62 from a position below the piston or bucket 66 to a position above the piston or bucket 66. From the foregoing description it will be seen that as the piston 31 moves downwardly, the piston 66 will move upwardly, and as the piston 31 moves upwardly, the piston 6D will move downwardly, these pistons 31 and 60 alternately moving toward and away from each other on the respective alternating strokes of the operating rod 32.

It will be noted from the foregoing that the externally threaded enlarged pipe 26 will provide a wide bearing and brace from the upper end of the operating rod to prevent bending. Furthermore, the structure as described will permit the interior mechanism to be entirely removed from thewell without removing the well casing to permit repairs or replacement to be made. Because of the structure described a minimum number of rods will be required for the operation of the pump, the actuation of the mechanically operated piston automatically causing the hydraulically operated piston to be actuated thereby facilitating the flow of liquid out through the discharge spout I8. It should be understood that the present device is particularly adapted for use in pumping oil, water, or other liquids 'from wells, particularly that type of well where the bore is necessarily small, and where the space for the operatingmechanism is necessarily restricted.

In Figure 11 there is shown a modied form of the invention wherein a piston rod 50a is illustrated having laterally extending arms 64 to which are secured piston rods 65 for actuating pistons 66 mounted within the cylinder 61 constituting booster pumps which communicate, as at 68, with the by-pass pipes 51a'.I similar to the bypass pipes 51 previously described. These additional pistons may be employed for boosting the hydraulic pressure if this should be found necessary by injecting pressure in the pipes 51a` intermediate the ends of the by-pass pipes, as well as at the ends thereof. It should be understood that the structure shown in Figure 11 is an optional structure embodying a modification wherein the cylinders 61 which constitute booster pumps are secured to the piston rod 50a which corresponds Ato the piston rod 5D shown `in Figure 4, these booster pumps being adapted to be located in a position below ythe housing 43 and just above ,the limit of the upward :stroke of the piston 6,0 illustrated in Figure 4. In Figures 7 and `8 there is shown a further embodiment lor modified form of the present invention illustrating va double type o f ,hydraulic piston, the structure previously described employing a single hydraulically operated piston and a mechanically operated piston. In the structure shown -in Figures '7 `and 8, a housing or casing 10 is illustrated carrying an upper tubular casing jI I andan intermediate tubular casing 12 and a bottom tubular casing 1,3. The upper tubular casing 'II is provided with an inlet pressure `pipe I4 communicating with the upper extreme end of the casing 'II and a piston rod 'I5 is slidably mounted -through 'the lower end of the casing 1|. This piston rod I5 is also slidably mounted in the upper end of the intermediate casing 12, Athe intermediate casing 'I2 having a central partition 16 yfor providing an upper compartment 12a, and a lower compartment 12b within the casing 72. A piston rod 'I'I has its upper end slidably mounted within the compartment 12b and the lower end of this rod Vl is reciprocably mounted Within the upper end of the casing 13.

A pair of by-pass pipes 'Iii communicate with the lower compartment 12b of the casing 'I2 and a pair of by-pass pipes 'i9 form a communication between the upper compartment 12a. of the casing 'I2 and the lower end of the casing I3 to act upon the lower end of the piston rod 1l. This structure is illustrated in Figure 7. A piston 8i! is anchored upon the piston rod l5 and is adapted to actuate therewith, the `by-pass tubes "I8 being slidably mounted through the piston fill and this piston being provided with flap valves 8| similar to the valves carried by the piston 3l described in the rst embodiment. The piston rod 'I1 also carries a lower piston 82 which is provided with Valves 83 similar to the valves carried by the piston 6l) described in the previous embodiment.

The operation of this structure just described, is as follows:-

Pressure enters the pipe 14 and forces the pisn ton rod I5 downwardly, moving the piston 8|! downwardly and allowing liquid to pass up through the valves 8|. Hydraulic pressure within the compartment 12a will travel down through the by-pass tubes or pipes 'IB and act upon the lower end of the piston rod 'll moving the piston 82 upwardly in an manner similar to that as described in the first embodiment. Upon the reversal of the pressure, the pressure will enter the pipes 'I8 and cause the parts to operate in a reverse manner spreading the pistons 8i) and B2 apart on the respective alternate strokes. The casings 1|, '12, and 'I3 are provided with suitable check Valves to facilitate proper and safe operation. It should also be understood that any type .of control mechanism may be employed for controlling the entrance of hydraulic pressure into, and the exhaust from, the pipes I4 and 18. From the structure shown in Figure 7 it will be observed that upon the direct operation of the piston Bil to produce a down stroke, the piston 82 will be actuated in a complementary manner through the passage of the hydraulic pressure through the by-pass pipes 19. Upon the return stroke, the pressure will pass down through the pipes 78 and act directly upon the piston 'Il to operate the piston 82 and in this instance the piston B will act complementary with the piston B2 as a result of the hydraulic pressure passing up through the pipes 19. M v

In the form shown in Figures 9 and 10 there is illustrated a structure for producing a hydraulically operated pump wherein I.|0 designates the well casing within which is mounted and spaced therefrom a special column joint I II at the bottomof the water column I I2. The pump cylinder IIB is mounted within the column I I2, as shown, and is .provided with an upper series of vports `I I4 and a lower series of ports ||5 separated by a baille plate or partition IIG.

A plurality of buckets or pistons I having valves IIB are located in the upper compartment ,I I9 and a plurality of buckets or pistons I Z having valves 12| are located in the lower kcompartment |22, the compartments IIS and |22 being formed by the partition IIE. The pistons IH and I2@ carry plungers |23 and |24 respectively working in cylinders and |26, the alternate cylinders being connected by the by-pass pipes I2?, as shown in Figures 9 and l0.

The cylinder H3 is anchored in position by means of a threaded neck |2'I fitting in a threaded socket S28 carried by the lower end of the column III and the lower end of the cylinder EIS abuts against the supporting shoulder or iiange |29, as shown in Figures `9 and 10. Hydraulic pressure may be initially supplied from any source of controlled supply by admitting pressure through the upper by-pass pipes l2?.

The operation of the structure shown in Figures 9 and 10 is as follows:-

On the down-stroke the liquid will pass up through the valves I2I in the bottom bucket and k the liquid in the lower vcylinder |26@ will be forced up through the pipe |2'l'd to the cylinder Itfb. Hydraulic pressure will also pass from the cylinder |25@ down through the pipe |2121 to the cylinder |260, the piston i2@ being moved apart within the compartment 22 and the pistons II'I will be moved apart in the compartment I 9. On the reverse movement, the pistons will be moved toward each other in this manner, providing the lifting action similar to that described in con-- nection with the foregoing forms.

Communicating ports |35) are formed between the interior .of the cylinder l i3 and the exterior of the vcolumn I I I, as shown in Figures 9 and 10. The structure illustrated in Figures 9 and l0 may be multiplied to provide as many compartments as may be desired without departing from the spirit yof the invention.

Having described the invention, what is claimed as new is:-

l. A pump of the class described comprising a casing, a cylinder within said casing, a mechanically operated piston head operable within said cylinder, a piston rod supporting said piston head and extending below said head, a housing comprising a pair of non-,communicating compartments adapted to contain hydraulic pressure, said piston rod tting in one compartment, a second piston rod slidably mounted within the other compartment of said housing below said iirst mentioned piston rod, lay-pass means forming a communication between the first mentioned compartment and the second mentioned compartment at a point below the second mentioned piston rod, a second piston head carried F by said second piston rod and located below said rst mentioned piston head within said casing, a second housing for receiving the opposite end of said second piston rod located below said iirst mentioned housing, by-pass tubes forming a lcornmunication between said housings for transmitting hydraulic pressure from one housing to the other as said rst mentioned piston rod is reciprocated, and valves formed in each piston for permitting the passage of liquid through the pistons in an upward direction as the pistons are reciprocated.

2. A pump of the class described comprising a casing, a cylinder within said casing, a mechanically operated piston head operable within said cylinder, a piston rod supporting said piston head and extending below said head, a housing comprising a pair of non-communicating compartments adapted to contain hydraulic pressure, said piston rod ttng in one compartment, a second piston rod slidably mounted within the other compartment of said housing below said rst mentioned piston rod, by-pass means forming a communication between the rst mentioned compartment and the second mentioned compartmient at a point below. the second mentioned piston rod, a second piston head carried by said second piston rod and located below said rst mentioned piston head within said casing, a second housing for receiving the opposite end of said second piston rod located below said i'lrst mentioned housing, by-pass tubes forming a communication between said housings for transmitting hydraulic pressure from one housing to the other as said rst mentioned piston rod is reciprocated, each piston having vertically extending ports, ap Valves covering the ports for swinging upwardly to permit of the passage of liquid through the pistons in an upward direction and preventing the passage of liquid in a downward direction, and said by-pass tubes passing through said second piston.

3. A pump of the class described comprising an outer casing, a removable barrel snugly tted within said outer casing, a mechanically operated piston slidably mounted within the barrel, a hydraulically operated piston snugly mounted within the barrel, hydraulic means actuated by the operation of said mechanically operated piston and in communication with said hydraulically operated piston below the hydraulically operated piston for simultaneously actuating the hydraulic operated piston, means for detachably anchoring the lower end of the said barrel within said casing, and means engaging the upper end of the barrel for facilitating the removal of the barrel from said casing. Y

4. A pump of the class described comprising an outer casing, a removable barrel snugly fitted within said outer casing, a mechanically operated piston slidably mounted within the barrel, a hydraulically operated piston snugly mounted within the barrel, hydraulic means actuated by the operation of said mechanically operated piston for simultaneously actuating the hydraulically operated piston, said hydraulic means having entrance and exit means below said hydraulically operated piston, means for detachably anchoring the lower end of said barrel within said casing, means engaging they upper end of the barrel for facilitating the removal of the barrel from said casing, said casing having an abutment shoulder for supporting the lower end of the barrel, said anchoring means comprising depending converging arms, and a threaded connection engaging the lower ends of said arms to provide anchoring means.

5. A pump of the class described comprising an outer casing having a discharge port at its upper end and an inlet at its bottom, a removable cover, an operating rod extending through and operating through said cover, an enlarged operating pipe engaging said operating rod, friction rings carried by said pipe, a barrel snugly fitted within said casing, guiding lugs carried by the outer face of said pipe for permitting reciprocation of the pipe and preventing rotation of the pipe in the barrel, a piston slidably mounted within said casing and carried by said enlarged pipe and provided with ports and upwardly opening check valves therefor, a piston rod depending from said piston, a hydraulic housing supported within said barrel, said housing comprising a pair of non-communicating upper and lower compartments, said piston rod working within the upper compartment, a second piston working within said barrel and provided with ports and upwardly opening check valves therefor, a hydraulically operated piston rod carried by said second piston with its upper portion working within the lower compartment, a second hydraulic housing below said rst mentioned casing, a piston rod suspended below said second piston and working within said second hydraulic housing, by-pass means communicating with the first mentioned compartment below the first mentioned piston rod and with the last mentioned hydraulic housing below the last mentioned piston rod, means for supplying hydraulic pressure to the second compartment for action against the second mentioned piston rod whereby the pistons may be caused to simultaneously operate in opposite directions as hydraulic pressure is applied and released, and a threaded anchoring means carried by the lower end of the barrel for securing the barrel in an anchored position.

6. A pump of the class described comprising an outer casing having an outlet at its top and an inlet at its bottom, a plurality of hydraulic housings within said casing and disposed one above the other, a piston slidably mounted within the casing and adapted to be reciprocated vertically through the action of hydraulic pressure forced into Vand out of said housings, the upper one of the housings having upper and lower non-communicating compartments, said piston having an upwardly extending piston rod and a downwardly extending piston rod, the upwardly extending piston rod working within the lower compartment of the housing and the downwardly extending piston rod working within the lower hydraulic housing, by-pass pipes establishing communication between the upper compartment of the upper housing and the lower hydraulic housing at a point below the lower end of the downwardly extending piston, and a working piston having a piston rod operating in the upper compartment of the upper housing for supplying and releasing hydraulic pressure to and from the lower housing and irnparting reciprocating movement to the rst piston.

7. A pump of the class described comprising an outer casing, upper and lower hydraulic housings within said casing, a piston slidably mounted within the casing and adapted to be reciprocated through the action of hydraulic pressure forced into and out of said housings, the upper one of the housings having upper and lower noncommunicating compartments, said piston having an upwardly extending piston rod working within the lower compartment of the upper housing and a downwardly extending piston rod working within the lower hydraulic housing, by-pass pipes establishing communication between the upper compartment of the rst mentioned housing and the lower hydraulic housing at a point below the lower end of the downwardly extending piston, means for supplying and releasing hydraulic pressure to and from the lower compartment of said rst mentioned housing in and for the purpose specified, .and pressure pumps operated by one of said piston rods and communicating with said by-pass pipes for boosting the hydraulic pressure within the by-pass pipes and housings.

8. A pump of the class described comprising a casing having an upper outlet and a lower inlet, a plurality of hydraulic housings, a plurality of pistons slidably mounted upon said casing and interposed between said housings, oppositely extending piston rods carried by each piston, a separate housing compartment for each oppositely extending piston rod, power operated means for initially controlling the admission and release of hydraulic pressure to one housing compartment, by-pass means forming a communication with one housing compartment below the piston rod operating therein and a compartment of an adjoining housing above the piston rod operating therein whereby movement imparted to one piston rod will cause a relative movement of all of the piston rods by alternately applying and releasing pressure in and for the purpose specified.

9. A pump of the class described comprising an outer casing, a column spaced therefrom having an inlet `at its bottom, a cylinder mounted within said casing and open at its bottom, said cylinder being divided into a plurality of compartments, a plurality of hydraulically operated pistons mounted within each compartment, hydraulic operating means having alternate communication above and below the alternate pistons to control the reciprocation of the pistons and cause successive pistons to move in opposite directions, and said cylinder having ports formed therein for facilitating the passing of liquid from the lower compartment to the compartment just above and provided with upwardly opening check valves.

10. A pump of the class described comprising an outer casing, a column mounted therein and spaced from the side walls of said casing and provided with a lower inlet and an upper outlet, a cylinder mounted within said column and spaced from said column, said cylinder and column having means forming a communication between the interior of the cylinder and the space between the casing and column, said cylinder having ports forming a communication between the interior and exterior of said cylinder, a partition for dividing said cylinder into a plurality of compartments, a plurality of spaced pistons mounted for reciprocating motion in each compartment, a plurality of non-communicating hydraulic housings mounted within each compartment one above the other, plungers carried by each piston .and iitting within each hydraulic housing, each piston having valves formed therein, the alternate hydraulic housings having a by-pass pipe connection whereby said pistons will alternately move toward and away from each other as hydraulic pressure is increased and decreased in the respective cylinders and uid forced upwardly in step-by-step movements as the pistons move upwardly, and means for initially supplying hydraulic pressure to the uppermost hydraulic housing, the by-pass pipe being connected to the next adjoining housing below the piston rod and to an adjoining housing above the piston rod whereby the movement of one piston rod downwardly will force the hydraulic pressure into the last mentioned housing and cause the corresponding piston to move downwardly and vice versa.

11. A pump of the class described comprising a casing having a lower inlet and an upper outlet, a piston slidably mounted near one end of said casing and formed with ports having upwardly opening check valves, a piston rod suspended below said piston, a hydraulic housing comprising a pair of non-communicating compartments one of which receives the lower end of said piston rod, a second piston slidably mounted within the other compartment of said housing below said iirst mentioned piston and formed with ports having upwardly opening check valves, said second piston having piston rods extending above and below, a second hydraulic housing receiving the piston rod below the second piston, the piston rod above the second piston extending into the second compartment of the first mentioned hydraulic housing, a by-pass establishing communication between the lower end o1 the first mentioned compartment under its piston rod and the upper end of the second mentioned compartment of the first mentioned housing above its piston rod, and means for supplying and releasing hydraulic pressure to and from the first mentioned compartment of the rst mentioned housing whereby said pistons may be simultaneously operated in opposite directions and fluid moved upwardly above the pistons in step-by-step movements.

12. A pump of the class described comprising a casing having a lower inlet and an upper outlet, a mechanically operated piston slidably mounted near one end of said casing and formed with ports controlled by upwardly opening check valves, a piston rod suspended below said piston, a hydraulic housing comprising upper and lower non-communicating compartments located below said piston, the upper compartment receiving the lower end of said piston rod, a hydraulic piston slidably mounted within said casing below said first mentioned piston and formed with ports controlled by upwardly opening check valves, said hydraulic piston having piston rods extending above and below, a second hydraulic housing receiving the piston rod below the second piston, the piston rod above the second hydraulic piston extending into the lower compartment of the rst mentioned hydraulic housing, means for supplying .and releasing hydraulic pressure to and from the lower compartment of the rst mentioned housing above its piston rod, and by-pass means forming a communication between the upper compartment of the first mentioned housing and the second mentioned hydraulic housing at a point below its piston whereby said pistons may be actuated and moved towards and away from each other for forcing fluid upwardly through the ports of the pistons and upwardly through the casing in step-by-step movements.

BURT C. WILLIAMSON. 

